The analysis of differential induction of hsp70 in the related cerebral domains and nerve fibers of rats after proteasome inhibiton.

Abstract

Parkinson's disease (PD) is popularly called "proteins conformation disease". Heat shock proteins (Hsps) are essential molecular chaperones that handle abnormal protein conformations. The hsp70 family, in particular, represents the most highly conserved molecular chaperones. They constitute a central part of a Ubiquitous-chaperone system. In the present study, we tested if the induction of hsp70 after proteasome inhibition follows a differential pattern in the related cerebral domains and nerve fibers of rats. We used RT-PCR, stereotactic delivery method and immunohistochemical analysis as the molecular tools of investigation. With regard to cerebral domains, the induction of hsp70 exhibited regionality and time-dependence. The intensity of hsp70 expression varied as follows: hippocampus > substantia nigra > frontal lobe > olfactory tract, especially following the order: CA3 > CA2 > CA1 in hippocampus. As for the nerve fibers, it was interesting to find that hsp70 induction was prominent in corpus striatum of lactacystin-treated rats, however hsp70 induction was not observed in the corpus callosum. Our study shows the differential induction of hsp70 in Dopamine (DA) nerve fibers and cerebral-association fibers, indicating that hsp70 could protect extrapyramidal system (corpus striatum), not pyramidal system (corpus callosum).